This award provides funding for synthesizing large quantities of conductive-core/transition-metal-oxide-shell nanocables on a highly flexible and strong carbon microfiber substrate. The primary goal of this work is to solve the three most critical limitations in supercapacitors for portable electronic devices and wearable electronics, i.e., inflexibility, low specific capacitance, and electrode failure resulting from ion insertion/extraction during charge/discharge cycling. The electrical conductive-cores will be used to support redox active transition-metal-oxide-shells with highly electrolytic accessible surface area and also to provide reliable electrical connections to the shells, enabling full utilization of transitional-metal-oxide and fast electronic and ionic conduction through the electrode. The carbon microfibers will offer not only flexibility and mechanical strength to the electrode but also more surface area than a flat conductive substrate for growing more nanocables, which further improves the specific capacitance and energy density. This research program will study the formation mechanisms of the core/shell nanocables grown on flexible carbon microfibers and the electrochemical energy storage mechanisms of the core/shell ? carbon microfiber hybrid composite electrodes. High throughput manufacturing of such composite electrodes with high flexibility, high specific capacitance, high energy density, high power density, fast charging/discharging rate, and long cycle life will be explored through the novel hierarchical nano/micro architecture design.
If successful, the results of this research will contribute to a better understanding of the manufacturing-structure-property-function of the core/shell ? carbon microfiber hybrid composites and their electrodes. This research has the potential to change the conventional concepts for flexible electrode design and to significantly impact existing electrode manufacturing technologies. The research advances made through this project will generate new knowledge that will be introduced to undergraduate and graduate students through existing courses and the research activities will be used as an educational platform for students at all levels to learn about nanomanufacturing and nanotechnology-enabled energy storage systems.